Template:On This Day (nonfiction)/March 29
1772: Astronomer, philosopher, theologian, and mystic Emanuel Swedenborg dies. A prolific thinker and writer, Swedenborg is best known for his book on the afterlife, Heaven and Hell (1758).
1780: Adventurer Jørgen Jørgensen born. He will sail to Iceland, declaring the country independent from Denmark and pronouncing himself its ruler, intending to found a new republic following the United States of America and France.
1873: Mathematician and academic Tullio Levi-Civita born. Levi-Civita will gain fame for his work on absolute differential calculus (tensor calculus) and its applications to the theory of relativity, and make significant contributions in other areas.
1873: Physicist and priest Francesco Zantedeschi dies. Zantedeschi was among the first to recognize the marked absorption by the atmosphere of red, yellow, and green light. He also thought that he had detected, in 1838, a magnetic action on steel needles by ultraviolet light, anticipating later discoveries connecting light and magnetism.
1896: Mathematician Wilhelm Ackermann born. Ackermann will discover the Ackermann function, an important example in the theory of computation.
1944: Mathematician Grace Chisholm Young dies. Young contributed measurable functions to the Denjoy–Young–Saks theorem, which gives some possibilities for the Dini derivatives of a function that hold almost everywhere.
1974: NASA's Mariner 10 becomes the first space probe to fly by Mercury.
2003: Physician and microbiologist Carlo Urbani dies of severe acute respiratory syndrome (SARS). Urbani identifed SARS as a new and dangerously contagious viral disease, and his early warning to the World Health Organization (WHO) triggered a swift and global response credited with saving numerous lives.